Tetanus is caused by a microorganism (an anaerobic bacterium, colostrum tetani that exists as a spore. These spores can be found in the soil and animal feces (horses, sheep, cattle, dogs, cats, guinea pigs, chickens).
These spores can enter the body through cuts and puncture wounds. Anaerobic (lack of oxygen) conditions allow spores to germinate and produce a potent toxin called tetanospasmin. It is this toxin that can cause the condition we know as Tetanus, commonly called lockjaw.
Between 1990 and 2000 there were 40-50 cases of tetanus per year in the U.S. (CDC, 2001). The majority of these cases were people over age 60 and intravenous drug users.
Tetanus is now recognized as primarily a disease of older adults in the U.S. On average less than 5% of tetanus cases occur in individuals less than 20 years of age. In 1999 only two cases of tetanus occurred in children.
Tetanus has been almost completely eliminated from the U.S., primarily because of good hygiene and proper wound cleaning.
For individuals who have had less than two previous injections of tetanus toxoid, an injection of Tetanus Immune Globulin, Human (TIG) is administered for serious wounds. This vaccine introduces antibodies directly into the body to fight tetanus bacteria.
The Vaccine Guide: Risks and Benefits for Children and Adults, Randall Neustaedter, OMD